Presidential contenders Michael Dukakis and Jesse Jackson headed into battle in Tuesday's Wisconsin primary on the heels of an inconclusive contest in Colorado. Jackson blasted the Colorado state chairman for "biased and politically unethical" actions in the slow-moving count.

Monday night's Colorado caucuses were a see-saw battle that saw first one and then the other gain the upper hand. When the state Democratic Party quit counting early Tuesdaymorning, Dukakis had 46 percent to Jackson's 40 percent, with just under half the precincts reporting.Dukakis had grabbed an early lead Monday night in the Colorado contest. But Jackson quickly caught up and even passed him when Denver results began coming in. Then Dukakis pulled ahead again.

Tuesday in Kenosha, Wis., Jackson complained that the dribble of caucus results from Colorado could have been delayed to give the appearance of a lead for Dukakis. Colorado Democratic chairman Buie Seawell, a Dukakis supporter, directed the count.

"This long and slow count represents a certain ineptness . . . it heightens suspicions," Jackson said. "You cannot very well be a fair referee and coaching another player."

Tennessee Sen. Albert Gore Jr. lagged far behind with 4 percent, and Sen. Paul Simon didn't get enough votes to count.

Simon, his campaign fading, said he hoped to score with Wisconsin's voters Tuesday. But he added: "If we don't do well, we have to make a re-evaluation. We'll take one step at a time." Pre-primary polls put Simon a distant fourth in Wisconsin.

On the Republican side, Vice President George Bush sailed to a strong lead in Colorado's GOP straw polls.

While voters were calling the shots in Wisconsin Tuesday, the candidates scattered to regroup for big-state contests coming up in New York, Pennsylvania and Ohio in the next month.

Dukakis sounded upbeat as he awaited the verdict in Wisconsin. "It looks good," he said as he arrived home in Boston Monday night. "We worked hard."

The four Democratic presidential hopefuls campaigned Monday across Wisconsin, with Jackson getting heat from rivals for his contact with Panamanian strongman Manuel Antonio Noriega.

Dukakis joined the criticism of Jackson. But that didn't stop Gore from saying the Massachusetts governor "gives the impression of being scared to death" to take on Jackson.

Dukakis, in turn, icily suggested Gore spend more time campaigning for votes and less time criticizing other candidates.

Although Bush has the GOP nomination wrapped up, former television evangelist Pat Robertson still contested Colorado, with its 36 delegates at stake.

Jackson and Dukakis made weekend campaign swings to Colorado trying to rally support for 2,784 precinct caucuses that began the state's delegate-selection process.